Active carbonaceous materials



Aug. 29, 1939. P. SMIT 2,171,408

ACTIVE CARBONACEOUS MATERIALS 7 Filed Sept. 17, 1955 2 Sheets-Shet 1 l II W I 12:71.

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Aug. 29, 1939. P. SMIT 2,171,408

' ACTIVE CARBONACEOUS MATERIALS 1 I Filed Sept. 17, 1955 2 Sheets-Sheet2 Patented Aug. 29,1939 1 2,171,408

UNITED STATES PATENT OFFICE ACTIVE CARBONACEOUS MATERIALS Pieter Smit,Amsterdam, Netherlands, assignor to N. V. Octrooien MaatschappijActivit, Amsterdam, Netherlands Application S p em r 17, 1935, SerialNo. 40,917 In France September 26, 1934 Claims. (Cl. 2523) My inventionrelates to catalysts, more espeand intensive intermingling of thereactantsfor cially of the large surface type, which is repreinstance byspraying the water-absorbing matesented for instance by the so-ca-ll'edactive carrial, such as concentrated sulfuric acid, in very bon, andmore especially to a carbonaceous matefine subdivision on thecarbonaceous material.

5 rial of great activity possessing certain properties Alternatively Imay intimately mix the two subof a colloid. stances or atomize them insuch a manner as to It is an object of my invention to provide cause anintermingling thereof, whereby the remeans for producing, in aparticular simple and action between them is brought about.

:effective manner, a material-of the kind afore- I may use any kind ofcarbonaceous material said, which is more efiiclent and better adaptedand amongst others such as have already served ,10 for practical usethan similar active materials in the purification of liquids. Suchsubstances hitherto known. are regenerated by this treatment.

Active carbon and other inert catalytic mate- In my copendingapplication for patent of the rials have frequently been used fordecoloration United States, Serial No. 1,265, filed January 10,

and the removal of offensive taste and smell in 1935, I have described amethod of acting on car- 15 liquid matter of all kinds. Hitherto activecarbon bonaceous material such as saw dust, wood meal,

. is mostly prepared by acting on coal or other sugar, coal and the likewith water-absorbing carbon with certain gases at a high temperature.chemicals including for instance sulfuric acid or Alternatively coal orthe like has been impregzinc chloride or calcium chloride, therebyproducmated with chemicals, which, when subjected to ing a productpossessing particular properties, for 20 the action of a hightemperature, are imparted instance a high ion-exchanging capacity. Inactivating properties. Steam, carbon dioxide, operating according to themanner aforesaid, I oxygen and chlorine have for instance been madeobtain a material possessing a predetermined to react with the carbon,and of the chemicals structure which renders it particularly adaptedused for impregnating the coal lime, caustic alkafor filtering under theform of layers. 25 lies, zinc chloride, sulfuric acid and the like mayIn contradistinction thereto the material obbe mentioned. The treatmentof the carbon with tained according to the present invention does suchgases or chemicals brings about a great not possess an outspokenstructure, but can very porosity of the carbon, whereby to this latteris readily be finely subdivided. While it is characimparted a very largesurface. The porous c'arterised by favorable decoloring and absorbing 30bon thus produced practically exerts only anabproperties, its mostcharacteristic property is that SOIDtiVG action, but no Chemical v ty,bei of separating out the colloidal matter forming substantially inert.In preparing it, care is taken part of the solutions and other liquids.to be filto raise the temperature asfar as possible in tered, and whichrender filtration very difficult 35, order to produce a carbon productof greatest and are the cause of froth formation. The new purity. Whenacting on, the carbon with one of material obtainable according to thisinvention the gases mentioned above, the temperature is as furtherpossesses a high ion-exchanging capacity.

a rule raised to about 800- 1100" C. When oper- It lends itself withparticular advantage to the ating with impregnation, lower temperaturesare improving of the properties of the soil, quite es- 40 used, sincethe action of the chemicals in question pecially in View of itsion-exchanging properties, 40 leads to a very fine subdivision of thismatewhereby all kinds of salts and fertilizing matter rial. However alsoin the practice of this method in general are fixed in the soil. It isfurther posavery high end temperature is reached. sible to bring theconstituents of this material I have now found that by changing thecondiinto a combination whereby a valuable fertilizer tions, under whichwater-absorbing chemicals reis formed. For instance, when-treating thecar- 45 act with carbonaceous materials, a catalyst posbonaceousmaterial with sulfuric acid or phossessing colloidal properties can beproduced. To phoric acid, these acids may be fixed by combinthis end Icause the water-absorbing chemical ing them with ammonia or magnesium.to mix with the carbonaceous material so inti- The new material, afterhaving been used for mately and with such intensity that a practicallydecoloration or other technical purposes, if mixed 50 instantaneousreaction is brought about between for instance with calcium compounds,will possess the two reactants and that a similarly instantagreatfertilizing properties. neous rise of temperature up to ZOO-250 C. as aA further great advantage consists therein that maximum'takes place. 7the new product can be produced at very low I succeed in bringing aboutsuch intimate cost; since only a small quantity of .Water-ab- 5bquickly.

sorbing chemicals is required and since in most cases outside heating inorder to bring about the reaction is superfluous. The sugar and glucoseproducing industries are particularly interested in an active materialof this kind. In order to render same fit for use for these purposes,care should be taken not to unnecessarily dilute the water-absorbingmaterial such as sulfuric or phosphoric acid. In any case thesematerials, after having been vpreheated, on being mixed with thecarbonaceous material must be capable of reacting with it directly andcausing the temperature to rise Although the material does not possess avery outspoken structure, provided that it is not subdivided to ofinely, it may be very useful for the purpose of filtration in a layer,similarly as bone black is used. In this case operation incountercurrent may be made use of, whereby a very great economy in theuse of the active matter is obtained. This treatment is, however,impracticable in cases where the liquid shows a great tendency todisperse the active material.

If the process is carried out under a certain pressure above normal bypreventing the gases developed in the reaction from escaping freely, thequantity of chemicals required to form the desired product may be keptlow, since under the action of a certain pressure above normal theimpregnation of the carbonaceous material is facilitated and improved.In order to obtain this I prefer causing the reaction to proceed in avessel or chamber which is almost or altogether closed.

I have found it useful, in order-to obtain a highly active product, toprovide for a rise in temperature such that the secondary condensableproducts formed in the reaction are at least partly volatilised, sinceotherwise they would render the product impure.

The preparation of a highly active material according to this inventionrequires only little time, as a rule not more than about ten minutes.

I have found that fine grinding of the mass. while i it is still hot, i.e. directly after preparation, is

advantageous for the production of an altogether homogeneous product,and this more particularly in those cases where the carbonaceousmaterial was not employed in high subdivision, for instance when actingon coarse wood meal.

Apart from the properties mentioned above the active carbonaceousmaterial prepared in accordance with the present invention furtherpossesses the following properties which must be taken into account whenputting it to practical use. It undergoes a dispersion in pure liquidsof alkaline reaction, whereby these liquids are colored. The presence ofimpurities in the liquid, for instance of albuminous matter, ofdissolved materials, etc., may prevent such dispersion from arising, andin these cases the active carbonaceous material will exert a purifyingaction on the liquid. This'dispersion is also counteracted by theformation of a precipitate or by the binding of the chemicals present inthe active material, and further by the presence of organic or inorganicreducing agents.

I have further found that dispersion of the active material is alsocounteracted by admixing to it or simultaneously adding insolublematerial such as earth, coal (more especially active coal), kieselguhr,fibrous matter, colloidal or suspended precipitates, flocculatedalbuminous matter and the like, but also dissolved materia s uc assodium chloride, calcium chloride, soluble albuminous matter, saponines,organic or inorganic reducing agents, etc., will act in a similar way.

Whenever the active material contains sodium, potassium or ammonium asexchangeable cations, dispersion will take place readily. Therefore,when purifying liquids which do not contain any constituents capable ofcounteracting such dispersion, it is desirable to replace these cationsby others, for instance by bringing the active material in contact witha solution of such other cations.

In order to be able to prepare the active material in the mosteconomical manner, I may use apparatus of different character. I mayoperate the process of preparation in a continuously or discontinuouslyactuated mixing apparatus, but in all cases care must be taken toprevent the formation of lumps in the reaction mass. A vertical orhorizontal double-armed stirring and mixing device may be used, in whichthe arms cooperate with edged ledges. Preferably the mixing deviceshould be connected directly with a grinding mill or other subdividingapparatus.

In the drawings aflixed to this specification and forming part thereofapparatus suitable for the carrying out of this invention areillustrated diagrammatically by way of example. In the drawings Figs. 1and 3 are axial sections, and

Fig. 2 is a perspective view, of a mechanical mixer which may be used inthe operation of the process, while Fig. 4 illustrates an apparatus formixing the substances .designed to react with each other by atomization.

Referring to the drawings and first to Fig. 1, A is the mixing vat, B isa. bottom slide for the exhausting of the contents, C is one of thestirring and mixing arms, .D is the opening for introducing thematerial, E is a container for the liquid reactant and F is a mill.

In Fig. 2 G is the mixing vat, while H is one of the mixing arms.

In Fig. 3 J is the mixing vat, K a horizontal shaft, L are the mixingarms fixed to the shaft, M is a hopper and N a receiver.

In Fig. 4 O is the atomizer vessel, P and R are containers for sulfuricacid and molasses under pressure, respectively, S and T are two atomizernozzles, U and V are pipes leading from the containers P and R to thenozzles S and T, respectively, W is a vent for the gases developed inthe reaction, which may pass through a dust separator, and X is a burnerserving to heat up the air in the apparatus before starting theoperation.

In the preparation of a material according to this invention I may forinstance proceed as follows:

' Example 1.-120 litres saw dust or wood meal are mixed in a mixer, forinstance such as shown in Fig. 1, with 40 litres sulfuric acid of 66 B.After the lapse of a few minutes the temperature rises to about 150 C.and about 10% by weight of the reactants escapes in the form of gases.At the end of ten minutes the mass, while still hot, is allowed to passthrough the mill to be ground therein.

Example 2.120 litres wood meal are mixed with to litres sulfuric acid of60 B., which has been preheated to about C. A vigorous reaction sets in,the temperature of the mixture rising to v C.

Example 3. litres wood meal or saw dust are mixed with a saturatedsolution of zinc chloride preheated to 120 C. At the end of ten minutesthe mass is passed through the grinding mill.

Example 4.-,To the mass prepared in accordance with Example 1 20 kgs.active carbon are added, before the mass is ground, and the mixture isthen passed through the grinding mill.

Example 5.To the mass prepared according to Example 1 60 kgs. dried andfinely ground clay are added, and the mass is then ground.

Example 6.--Molasses preheated to 80 C. and sulfuric acid of 66 B. areatomized in an apparatus such as illustrated in Fig. 4, in theproportion of one part by volume sulfuric acid to 0.5-4.5 parts molassesin such a manner that the atomized substances thoroughly penetrate eachother. In the operation of this process about ten parts of a flakyactive material are formed instantaneously.

Various changes may be made in the details disclosed in the foregoingspecification without departing from the invention or sacrificing theadvantages thereof.

I claim:

1. In the manufacture of catalytically active carbonaceous materialshaving colloidal properties, the process which comprises finelysubdividing a solid carbonaceous material, which has the property ofyielding carbon when subjected to dry distillation, and quickly mixingthe finely subdivided product with concentrated sulfuric acid having aconcentration of over approximately 60 B., the rate and conditions ofmixing being such that the formation of lumps is avoided, that aninstantaneous reaction is produced throughout the whole mass which iscompleted to give a final product within a period not exceeding 10minutes and that a substantially instantaneous rise in temperature to amaximum of not below 150 C. and not substantially above 250 C. iscaused, whereby a rapid volatilization of secondary condensable productsformed in the reaction takes place.

2. The process of claim 1 wherein the acid used is suflicientlyconcentrated to produce said reaction when mixed with said carbonaceousmateriar at room temperatures.

3. The process of claim 1 wherein the acid used is preheated prior toadmixture with the carbonaceous material to temperatures sufllcient- 1yhigh to produce the described reaction.

4. The process of claim 1 wherein said reaction is conducted in a closedreaction zone preventing the escape of the volatilized products.

5. The process of claim 1 wherein the solid products resulting from thereaction are ground while still hot.

PIETER SMIT.

